The present invention relates to the fields of apparatus and methods for the subcutaneous placement of catheters, and more particularly to a novel subcutaneous tunneling instrument and method of utilizing the same.
The desirability and methods of utilizing small subcutaneous permanent home hyperalimentation catheters of the Hickman or Broviac type are known in the art and are discussed in various journal articles. An exemplary technique for using a Broviac type catheter is described in an article entitled "Technique for Placement of a Permanent Home Hyperalimentation Catheter," by David M. Heimbach, M.D., and Tom D. Ivey, M.D., Surgery, Gynecology & Obstetrics, October 1976, Volume 143, pp. 635-36, which is incorporated herein by reference. An exemplary technique for using a Hickman type catheter is described in U.S. Pat. No. 4,432,752, "Procedure for Introducing Hyperalimentation Catheters and the Like," issued to Marlon on Feb. 24, 1984, which is also incorporated herein by reference.
Also known are the desirability and methods of utilizing long subcutaneous catheters in neurosurgery, ventricular, and peritoneal shunts, which are also discussed in various journal articles.
Known methods of placing subcutaneous permanent home hyperalimentation catheters involve the forcible, trauma inducing formation of a subcutaneous catheter tunnel through which the desired catheter is to be led. In the prior art, subcutaneous tunnels have been formed by means of forcing blunt, trauma inducing tunneling instruments along the selected subcutaneous path or by utilizing instruments having sharp blades at their proximate ends that literally and indiscriminately cut through subcutaneous tissue, both fatty tissue and blood vessels alike. Examples of tunnelling instruments of the former category are the vaginal packing forceps disclosed in the Heimbach article cited above, or the somewhat less traumatic blunt-nosed rigid tunneling catheter disclosed in U.S. Pat. No. 4,432,752 to Marlon.
Another known tunnelling instrument is a stainless steel trocar, which is a sharp-pointed instrument fitted within the lumen of a reusable cannula sheath, which is forced along the desired subcutaneous path to create the subcutaneous tunnel. However, not only does the sharp point of the instrument undesirably cut subcutaneous tissue as it is tunnelled though tissue, but the forward edges of the cannula sheath also tear at subcutaneous tissue as the trocar is forced along its path. Once the desired subcutaneous tunneling has been completed, the stainless steal instrument is removed from the lumen of the cannula sheath, which remains in place, and the catheter of choice is fed through the lumen of the cannula sheath. The cannular sheath is then removed from the subcutaneous tunnel by slipping the cannula sheath off of the indwelling catheter. A device of this type is known in the art as the Steiger Tunneling Instrument, which is available commercially through Evermed of Kirkland, Washington.
The novel tunnelling instrument of the present invention provides for less traumatic placements of permanent home hyperalimentation catheters and shunts than has heretofore been known in the prior art.